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• avcodec/utils : only warn when passed invalid lowres value

  5 août 2016, par Aman Gupta

  avcodec/utils : only warn when passed invalid lowres value
  This makes it easier to use the lowres option when dealing with input
  
  files in different codecs. If the codec doesn’t support lowres=1 for
  
  instance, it will throw a warning and use lowres=0 instead of erroring
  
  out completely.
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/utils.c

• Getting 'av_interleaved_write_frame() : Broken pipe' error

  2 juillet 2016, par Poornan

  I am trying this blog post.I am new to python, numpy as well as FFMPEG. I could not figure out what causes this issue.

  http://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/

  here is the code :

  import subprocess as sp
  
  import numpy
  
  
  
  print ("Hello World!");
  
  FFMPEG_BIN = "ffmpeg" # on Linux ans Mac OS
  
  #FFMPEG_BIN = "ffmpeg.exe" # on Windows
  
  
  
  command = [ FFMPEG_BIN,
  
              '-i', '/Users/eananthaneshan/Movies/myvideo.mp4',
  
              '-f', 'image2pipe',
  
              '-pix_fmt', 'yuv444p',
  
              '-s', '420x360',
  
              '-r', '24',
  
              '-vcodec', 'h264', '-']
  
  pipe = sp.Popen(command, stdout = sp.PIPE, bufsize=-1)
  
  
  
  # read 420*360*3 bytes (= 1 frame)
  
  raw_image = pipe.stdout.read(420*360*3)
  
  # transform the byte read into a numpy array
  
  image =  numpy.fromstring(raw_image, dtype='uint8')
  
  image = image.reshape((360,420,3)   )
  
  # throw away the data in the pipe's buffer.
  
  pipe.stdout.flush()

  This is the output :

  ffmpeg version 2.8 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 7.0.0 (clang-700.0.72)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.8 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-opencl --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libfreetype --enable-libtheora --enable-libvorbis --enable-libvpx --enable-librtmp --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libass --enable-ffplay --enable-libspeex --enable-libschroedinger --enable-libfdk-aac --enable-libopus --enable-frei0r --enable-libopenjpeg --disable-decoder=jpeg2000 --extra-cflags='-I/usr/local/Cellar/openjpeg/1.5.2_1/include/openjpeg-1.5 ' --enable-nonfree --enable-vda
  
    libavutil      54. 31.100 / 54. 31.100
  
    libavcodec     56. 60.100 / 56. 60.100
  
    libavformat    56. 40.101 / 56. 40.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 40.101 /  5. 40.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.101 /  1.  2.101
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/eananthaneshan/Movies/myvideo.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isom
  
      creation_time   : 2014-04-07 02:02:31
  
    Duration: 01:00:10.03, start: 0.000000, bitrate: 1024 kb/s
  
      Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 111 kb/s (default)
  
      Metadata:
  
        creation_time   : 2014-04-07 02:02:31
  
        handler_name    : GPAC ISO Audio Handler
  
      Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709/unknown/unknown), 720x404, 909 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-04-07 01:14:58
  
        handler_name    : L-SMASH Video Media Handler
  
        encoder         : AVC Coding
  
  Output #0, image2pipe, to 'pipe:':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isom
  
      encoder         : Lavf56.40.101
  
      Stream #0:0(und): Video: rawvideo (444P / 0x50343434), yuv444p, 420x360, q=2-31, 200 kb/s, 23.98 fps, 23.98 tbn, 23.98 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-04-07 01:14:58
  
        handler_name    : L-SMASH Video Media Handler
  
        encoder         : Lavc56.60.100 rawvideo
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (h264 (native) -> rawvideo (native))
  
  Press [q] to stop, [?] for help
  
  av_interleaved_write_frame(): Broken pipe
  
  frame=    2 fps=0.0 q=-0.0 Lsize=     886kB time=00:00:00.08 bitrate=87003.8kbits/s    
  
  video:886kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%
  
  Conversion failed!

• compile ffmpeg decode only without audio codecs

  28 juillet 2016, par Rob

  I work on a media manager and use ffmpeg.exe to extract screenshots.
  With the latest size of ffmpeg.exe exceeding 35MB, I am attempting to build ffmpeg without the majority of its functions, to allow only saving of a frame of video.

  I had thought disabling many of the filters, Audio Codecs etc would shrink the size of ffmpeg to something more manageable.

  Following this guide
  https://pracucci.com/compile-ffmpeg-on-windows-with-visual-studio-compiler.html
  to allow building of ffmpeg using Visual Studio 2015, I have come to the part of ./configuration and hit a wall.
  With so many options and no idea what all of them mean or do, I am asking if someone in the community can give me laymans instructions.

  I also know that I need to build x264, and possible x265 (HEVC), but am not sure if there is anything other codecs needed.
  In the end, I and am hoping to just have the one file, ffmpeg.exe for use in the media manager project.

  The code I use to get a screenshot is as follows

  Public Shared Function CreateScreenShot(ByVal FullPathAndFilename As String, ByVal SavePath As String, ByVal sec As Integer, Optional ByVal Overwrite As Boolean = False) As Boolean
  
      If Not File.Exists(SavePath) Or Overwrite Then
  
          Try
  
              IO.File.Delete(SavePath)
  
          Catch
  
              Return False
  
          End Try
  
          If IO.File.Exists(FullPathAndFilename) Then
  
              Dim myProcess As Process = New Process
  
              Try
  
                  Dim seconds As Integer = sec
  
                  myProcess.StartInfo.WindowStyle = ProcessWindowStyle.Hidden
  
                  myProcess.StartInfo.CreateNoWindow = False
  
                  myProcess.StartInfo.FileName = Utilities.applicationPath & "\Assets\ffmpeg.exe"
  
                  Dim proc_arguments As String = "-ss " & seconds.ToString & " -i """ & FullPathAndFilename & """ -vframes:v 1 -an " & """" & SavePath & """"
  
                  myProcess.StartInfo.Arguments = proc_arguments
  
                  myProcess.Start()
  
                  myProcess.WaitForExit()
  
                  If File.Exists(SavePath) Then Return True
  
              Catch ex As Exception
  
                  Throw ex
  
              Finally
  
                  myProcess.Close()
  
              End Try
  
          End If
  
      End If
  
      Return False
  
  End Function

  I hope this is sufficient information, and appreciated any help or suggestions.